Charley's idol, the Man With Nine Lives, is coming to town to perform a series of high risk very dangerous do-not-ever-try-at-home motor cycle stunts. Only problem is Mona and pals have detected a Mechanical Mayhem Gremlin lurking about town causing trouble in the local machinery - and even Charley's bicycle. Going over the Man With Nine Lives's press kit reveals he has already used up his nine lives and has no more to spare. This means they've got to stop the Mechanical Mayhem Gremlin or stop the Man With Nine Lives from doing his show. But how do you stop a guy who uncannily resembles Charley thirty years in the future and who is just as determined as a ten year old? Maybe it would be easier to stop the gremlin. / During a freak electric storm, Mrs. Vanderplatz's greenhouse is struck by lightning. The combination 40 000 volt jolt and the vitamin-enriched soil bring to life a creature the likes of which the world has never known a giant, horrific...YAMMERING YAM! It isn't long before the roaming root vegetable is running roughshod through town. Mona sounds the alarm, but her warnings fall on deaf ears. The rest of the town is too busy preparing for that weekend's pot-luck picnic. So after a quick costume change, Mona must go it alone as Mona the Chef, armed with nothing more than a potato peeler and a battery-operated mixer. In the end, order is restored, the townspeople are none the wiser, and Mona's enormous tub of Yam Surprise is the hit of the potluck picnic.